Soil zinc content, groundwater usage, and prostate cancer incidence in South Carolina.
BACKGROUND
Prostate cancer (PrCA) incidence in South Carolina (SC) exceeds the national average, particularly among African Americans (AAs). Though data are limited, low environmental zinc exposures and down-regulation of prostatic zinc transporter proteins among AAs may explain, in part, the racial PrCA disparity.


METHODS
Age-adjusted PrCA rates were calculated by census tract. Demographic data were obtained from the 1990 census. Hazardous waste site locations and soil zinc concentrations were obtained from existing federal and state databases. A geographic information system and Poisson regression were used to test the hypothesis that census tracts with reduced soil zinc concentrations, elevated groundwater use, or more agricultural or hazardous waste sites had elevated PrCA risks.


RESULTS
Census tracts with high groundwater use and low zinc concentrations had higher PrCA rate ratios (RR: 1.270; 95% confidence interval: 1.079, 1.505). This effect was not more apparent in areas populated primarily by AAs.


CONCLUSIONS
Increased PrCA rates were associated with reduced soil zinc concentrations and elevated groundwater use, although this observation is not likely to contribute to SC's racial PrCA disparity. Statewide mapping and statistical modeling of relationships between environmental factors, demographics, and cancer incidence can be used to screen hypotheses focusing on novel PrCA risk factors.
Wagner
Sara E
SE
Cancer Prevention and Control Program, University of South Carolina, 2221 Devine Street, Columbia, SC 29208, USA. wagnerse@mailbox.sc.edu
Burch
James B
JB
Hussey
Jim
J
Temples
Tom
T
Bolick-Aldrich
Susan
S
Mosley-Broughton
Catishia
C
Liu
Yuan
Y
Hebert
James R
JR
D001741:Black or African American / Q000706:statistics & numerical data; D000368:Aged; D001499:Bayes Theorem; D019352:Censuses; D003710:Demography; D004781:Environmental Exposure / Q000009:adverse effects*; D005618:Fresh Water / Q000737:chemistry*; D005843:Geography; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008390:Markov Chains; D008875:Middle Aged; D009010:Monte Carlo Method; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology; D012189:Retrospective Studies; D012987:Soil / Q000032:analysis*; D013022:South Carolina / Q000453:epidemiology; D013223:Statistics as Topic; D044465:White People / Q000706:statistics & numerical data; D015032:Zinc / Q000032:analysis*
D012987:Soil; D015032:Zinc